Help with HIIT

[JimBo123]

After reading the information in the post here

http://training.fitness.com/showthread.php?s=&threadid=18&highlight=hiit

I decided that i wanted to start using this method of training. I've used it twice so far for running in the afternoon and i have to say... im a little confused.
My lvl 10 or 100% would be a fast sprint, that is if i was going from lvl 0 to lvl 10. But, by the time ive gone 5 minutes, and im doing my lvl 9, i cant push myself to sprint or else ill be dead tired. So instead of sprinting i just go at a fast run. Is this correct? Will my lvl 9 and lvl 10 be lowered if im already running from lvl 5 up to lvl 9 for 5 minutes?
Also im only able to do this for 10 minutes, even in the afternoon. I cant imagine how little ill be able to do in the mornings when im very tired. Input would be appreciated thanks.

 

[Ethan01]

Lower your lv10 so that you are able to get there 2-3 times...after youve done this for about 3-4 weeks youll start to go faster, longer, better, etc.

 

[dswithers]

Another effective way to do HIIT is to do a 15-60 second all out burst followed by a 1-2 minute "active" rest period. Repeat that cycle 6-8 times. For example, sprint 100 yards, walk slowly back to the starting point and repeat. You can do any strenuous exercise this way: swimming, rope jumping, hill sprints, rowing machine, eliptical trainer, bends and thrusts, bear crawls, squats, etc. Whatever you have available and feel like doing. Obviously, the most effective is the one that most winds you the most (or elevates your heart rate the highest).